Automatic safety reel for airplane pilots



Jarl- 24, 1956 J. c. WHITTINGHAM x-:TAL 2,732,149

AUTOMATIC SAFETY REEL FOR AIRPLANE PILOTS Filed Jan. 4, 1954 2 Sheets-Sheet l ALw a ATTORNEYS Jan. 24, 1956 J. c. wHrr'nNGHAM Erm. 2,732,149

AUTOMATIC SAFETY REEL FOR AIRPLANE PILOTS 2 Sheets-Sheet 2 Filed Jan. 4, 1954 'INI/ENTOR. .702m GWh/fh):

gba/27 A T TRNVS United States Patent O AUTOMATIC'VSAFETY REEL FOR AIRPLANE PILOTS John C. Whittingham and Proctor W. Nichols, Colorado Springs, Colo.

Application January 4, 1954, Serial No. 402,031

6 Claims. (Cl. 242-107) This invention relates to improvements in safety devices for use more particularly by airplane pilots and passengers, but which is also adapted for use by automobile pilots and passengers and relates with greater particularity to an improved automatic reel mechanism for taking up the cable attached to a shoulder harness and for permitting the cable to be unreeled at a moderate speed to permit free movement of the pilot or passenger and which will automatically latch when the cable is subjected to a quick jerk thus preventing the person from being catapulted forwardly. As an example of such devices, attention is called to U. S. Patent 2,434,119, June 6, 1948.

It is the object of this invention to produce an automatic reel of the type indicated that shall be of light weight and of a comparatively simple construction.

Another object is to produce an automatic reel of the type indicated, which shall be provided with a spring rewind mechanism of such construction that it will exert a substantially constant torque at every stage of the unwinding and rewinding operation.

A further object is to produce a device of the type indicated that shall have means for eiecting adjustments that will enable the latching of the reel to be adjusted to any desired rate of cable rewind acceleration.

The above and any other objects that my become apparent as the description proceeds are attained by means of a construction and an arrangement of parts that will now be described in detail, for which purpose reference will be had to the accompanying drawings in which the invention has been illustrated in its preferred form, and inwhich,

Figure l is a top plan view of the device, portions of the cover having been'brokcn away to better disclose the construction.

Figure 2 is a section taken on line 2 2 Fig. l and shows the latch control mechanism in automatic lock position.

Figure 2a is a section also taken on line 2 2 of Fig. l and shows the latch control mechanism in manual lock position.

Figure 3 is a section'taken on line 3 3 Figures l and 3.

Figure 4 is a fragmentary section taken on line 4 4 Figures 2 and 5.

Figure 5 is a side ure 4.

Figure 6 is a fragmentary bottom plan view of the toothed lower surface of the rotary drum and a section of the friction pinion, taken on line 6 6 Figure 3.

Figure 6a is a fragmentary side elevational view of the rotary drum, looking through plane G11-6a Figure 6.

Figure 7 is a fragmentary section taken on line 7 7 Figure 3.

Figure 8 is a section taken on line 8 8, Figure 3, and

Figure 9 is a fragmentary perspective view showing elevation looking upwardly in Fig- "ice a portion of the inner gear toothed surface of the rotor and its relation to the friction pinion.

Referring now to the drawing, reference numeral 10 designates a base which is preferably made from aluminum, magnesium or from some alloy of low specific gravity and is preferably a casting. The base is provided with an upwardly extending pivot 11. Surrounding the pivot and concentric therewith is a circular ridge 12 whose upper surface is provided with ratchet teeth 13. Surrounding the central pivot is an annular high power permanent magnet 14 of the Alnico type which has its poles at the top and the bottom. Mounted for rotation on pivot 11 is a drum which has been designated as a unit by reference number 15. The drum is circular and has a central hub 16. An annular recess is formed in the inner surface of drum 15 between the hub and the cylindrical wall 19 that is provided with gear teeth 18 that are inclined as shown in Fig. 9. The lower surface of the annular outer wall 19 is provided with ratchet teeth 13a which in the position of the drum shown in Fig. 2a interlock with teeth 13 on the raised portion 12 and latch the drum against rotation in the clockwise direction when viewed as in Fig. l. The drum is made from magnetic material and when it is in the position shown in Fig. 2a the lower end of hub 16 will be in engagement with the upper surface of magnet 14 which serves to hold it in interlocked position until the drum is raised to the position shown in Fig. 2 by means which will be hereinafter described. The drum and the parts already described are enclosed by a removable cover 20 that is held in place by a screw 2l that has threaded engagement with pivot 11 as shown in Figures l and 3. Attached to the inner surface of the cover by screws 22 are annular magnets 23 that serve to hold the drum in its uppermost position as shown in Figures 2 and 3 until it is separated from the magnets by a force exerted thereon by a control means that will presently be described. A pivot 24 extends upwardly from the base as shown in Figures 3 and 6 and mounted for rotation thereon is a pinion 25 that has inclined or helical teeth that cooperate With teeth 18 on the drum. :From Fig. 3 it will be seen that the upper end of the opening in pinion 2S is larger than the pivot so as to provide an annular space that is at least partly lled with a yieldable material 26 such as felt. A cup washer 17 is adjustably attached to the upper end of pivot 24 with its side edge resting on the felt packing that surrounds the pivot. By varying the compression of the felt or other equivalent packing material the resistance offered to the rotation of this pinion on the pivot can be regulated or adjusted to produce the optimum operation of the device. The outer or peripheral surface of the drum has two parallel grooves designated by numerals 29 and 30, the iirst mentioned groove being for the reception of cable 31.. One end of the cable is attached to the drum in any suitable manner and is Wrapped several times around the drum. ln the drawing the cable has been shown as encircling the drum twice but any greater number of turns can be used. The cable passes to the outside through a tangential opening in the dust cover 32 and terminates in a ring 33 or equivalent means for effecting connection with the safety harness which has not been shown and is shown in many patents in Class -189.

The permanent magnets 23 serve to hold the drum in the position shown in Figures 2 and 3 while the magnet 14 holds the drum in the latched position shown in Fig. 2a. The position shown in Fig. 2 will be referred to as the automatic lock position and the one shown in Fig. 2a will be referred to as the manual lock position.

The control device will now be described. Attention has already been called to peripheral groove 30 with which the control device cooperates by means of pin 34 that projects from the slide 35. Projecting outwardly Y si) from the other'side of the slide are two'vertically spaced pins 36 and 37 (Fig. 5). SlideV 35 is guided in its movements in a channel formed by a metal strip whose shape is most clearly shown in Figures4 and 5 The guideY memberlis formed from sheet metal having av central out- V wardly facing guide channelwhose side walls have been control cam member that extends through the last mentioned openings in the manner` shown most clearly in Figures 2, 2a, 4 and 5 to which reference will now be had. Cam member 43 is constrained in its vertical movements by the slots in walls 39 and 39a as most clearly shown in Figures 2- and 2a and is provided on its top edge with atriangular cam 44 and is also provided on its lower edge with a cam surface 45. The distance from the lower edge of the cam member to the vertexV of the triangularY cam has been designated by a in Fig. 5 and is substantiallyequal to the clear distance between pins 36 and 37 and the end of the cam member to the right of camsurface 45 is also equal'to a. The left hand end of member 43 projects to the outside of the cover when in thecposition' shown in Fig. 2 as well'as when the parts are inthe position shown in Fig. 2a. A somewhat rigid push andpull wire 46 is connected to the left hand end of cam 43 and extendsV tothe control lever 48 that has two positions, one corresponding to the automatic lock position shown in Fig.- 2 and the other corresponds to the manual lock position shown in Fig. 1 and Fig. 2a. A spring 49 tends to keep lever 48 in each of its two positions. Wire 46 passes through a flexible tube 50 such as a closely coiled wire helix. A second wire 46a extends to a point near the pilot seat and terminates in a ring 51 or other equiva-Y lenthand grip that canY be grasped by the pilot for controllingethe latch device.

Flexible tubes V50 have one end anchored to bracket 51 by means of a clamp 52 and the other ends are also clamped Vby suitable means to a stationary member. The-rocking of control handle 48 shifts the cam member between the two positions shown in Figures 2 and 2a. If cam member 43 is in the position shown in Fig. 2 itc'an-be shifted to the locking position shown in Fig. 2a by a pull on hand grip 57. Y vIt has been explained above that slide 35 has a pin 34 that projects into groove 30 and that slide 35 has two the cam member 43 is kmoved towards the left to the position shown in Figure 2a itkforcibly moves drum 15 into 'locking position.

It is necessary that'the drum shallbe subjected to the Y action of a spring that will rotate itin a direction to wind the cable thereonto when the tension in the cable is reduced below a certain amount. The rewinding force is usually providedA by a spring of the type used in clocks and such springs are shown in many patents and U. S. Patent 2,480,335 is an example. Such springs have a shortrange'of operation in proportion to the space they occupy and one of their characteristics is that the torque exerted by them increases in direct proportion to the extent that they are wound. Instead of employing the usual clock spring type of spring another type is used which occupies less space and has the peculiar property of opposing a constant resistance to any force tending to unwindit. Suchspringsare old and have been selected because. their characteristic. fcaturesmake: them most ,suitable for the function which they are to perform. Y

Referring now to Figures 3, 7 and' 8, it will be seen that a pinion 51 which has been illustrated as provided with an integral hub52 whose lower end is journaled in a bearing 53 in the base, is inoperative engagement with gear 18 as shown in Fig. 7'. Attached to the base at a point somewaht removed fromhub- 52- is a round pin 54 about which is mountedl for free rotation a clock spring 55. The other end of the spring is. anchored to hub 52 andby rotating pinion Bland hub 52 in a clockwise direction the major portion of the spring is transferred onto hub 52. Since the springV has a permanent set that tends to coil it onto pin 54 it is evident that it must be bentY in the opposite direction for winding it onto hub 52 and thatV it therefore has a tendency to return to pin 54. In.

this ca se there is no longitudinal tension applied to the spring. The theory on which Vthis motor operates is wellY known and no further'explanation will be given.

Operation in Fig. 2, and that4 the cable is fully wound onto theY drum. By exerting a pull on. the cable sucient to unwind it from. the drumthe latter will tum in a clockwise direction and produce. a corresponding rotation of pinions 25 and 51 thereby coiling more of springSS onto hub 52. When the tensionzinthe cable is releasedy the action of. springzSS wilt produce a counter-clock rotation of the drum. This. freeY unwinding and winding of the cable permitsY theY pilot to move about suciently to perform` his duties. intheA event .of `a threatened collision or of some dangenthe pilot willmove quickly and jerk the cable. TheV friction of. pinion 25- and; its inertia will cause a suicient downward; force to beV produced by the interaction of theihelical. gear. teeth. to pullv the drumV away from magnets23.- and bringhubfl into engagement withY magnet114: inwhich positionthe ratchet teeth 13 and 13a will interlock and prevent furtherrotation ofV the drum.. This automatic locking of the. drum prevents'thepilot or passenger from. being catapulted forwardly in the event'of'asuddenstop. To release-thev lock the operator moves the: cam member 43. towardsv the-left thereby returningpin 3.7 (which was moved downwardly to. the level vshown inFig. 2a.when.the. drum moved'into locked position) and drum to the position shown inFigfZ in which positionV magnetsZS: become eiective and hold the drumfrom falling dowmuntilr it issubjected' either to a force produced bythe interaction of the vhelicalor inclinedf gearteethorfbyfa movement of the cam. lever from. the :position shownin. Figures 2. and 5. to ther posi-v tion shown in Fig. 2a. 1f the pilot or passengerislfearful ofA a .possiblesuddenz stoppage", the. cam member. is. manually moved. to` theY position shown in Fig. Zaby shifting lever 48 from the automatic lock position to the manual lock positionshown in Fig..2; thisf can alsozbeeffected by a pull on wire 46a. Y

Attention is called. inaparticularA te. the following features:

(A) The drum.. has'. inclined. helical or. inclined gear teeth 18 as shown most clearly in Fig. 9 and pinionV 25 has correspondinglyinclinedtteethfandcisnot freely.r rotatable. on pivot 24fhut is'provided-with:means'zsuchzas'the compressedfelt 261tliat produces a frictioudragfwhich is suicient tofpull tliegdrumV away fromtthemagnets 23 if-the cable jerked. with sucient force to.. start; the drum quickly. Y Y

The use ofthehelical'erinclincdigeargteethto: produce the locking force is also believed to be novelzin'lliis type ot device asawell-.asf the meansgfor-controlling the frictional resistance to rotation of pinion 25.`

The use. of.: the.type1 oi springsmotor shown and described is important for the reason that it is compact, light, exerts a substantially constant force throughout its entire range and tits into the same annular space as pinion 25.

Special attention is directed to the means for moving the drum om upper or unlatched position to the lower or latched position shown in Figures 2, 2a, 4 and 5.

What is claimed as new is:

1. A safety anchoring device of the class described comprising a base having a pivot projecting upwardly therefrom, a ring of ratchet teeth surrounding the pivot in coaxial relation thereto, a cylindrical drum having a central hub mounted for rotation on said pivot, the drum having a peripheral wall spaced from the hub to provide an annular chamber, the concave surface of said wall having helical gear teeth forming an internal helical gear, the edge of the wall facing the base having ratchet teeth positioned for operative latching engagement with the ratchet teeth on the base when the drum is in its lowermost position, a permanent magnet carried by the base in position to be operatively engaged by the lower end of the hub when the drum is in latched position, a stationary pivot projecting upwardly from the base into said annular chamber, a helical pinion mounted on the last named pivot in position to operatively engage the teeth on the internal gear, an adjustable friction means operatively positioned between the pinion and the last named pivot for providing an adjusted resistance to turning of the pinion, a cover enclosing the drum, at least one permanent magnet carried by the cover in position to support the drum in raised unlatched position the outer surface of the drum having a groove, a cable wound about the drum in the groove, means comprising a spring motor positioned in the annular chamber and operatively nterconnecting the drum and the base, positioned and arranged to rotate the drum in a direction to wind the cable onto the drum, and manual means for moving the drum from its latching position to unlatched position adjacent the magnet carried by the cover.

2. A device in accordance with claim 1 in which the friction means comprises a compressible material positioned in an annular space within the pinion immediately surrounding the pivot, and in which means is provided for compressing the material to adjust its friction elect.

3. A device in accordance with claim 1 in which the drum has two parallel grooves in its peripheral surface and in which the manual means for shifting the drum along its pivot, comprises a slide mounted for vertical movement adjacent the outer surface of the drum and is provided with a pin that projects into one of the grooves and in which a means comprising a manually shiftable cam is operatively associated with the slide to move it in a direction to shift the drum along its pivot.

4. A safety device of the class described, for pilot seats subject to rapid deceleration, forming a connection between a safety harness and the seat, comprising a base for attachment to the seat, a pivot projecting from the base, a drum pivotally mounted on the pivot, said base and drum having drum latching means comprising opposed ratchet teeth, a cover for the drum, permanent magnets attached to the cover in position to support the drum in freely rotatable position, the side of the drum facing the base having an annular chamber concentric with the pivot, the inner surface of the wall surrounding the annular chamber having helical gear teeth forming an internal gear, a helical pinion pivotally mounted on the base in position for operative engagement with the internal gear, friction means operatively associated with the base and the pinion, means for adjusting the eiectiveness of said friction means to vary its resistance, the drum having a cable groove in its peripheral surface, a cable having one end fastened to the drum and wound about the drum in the groove, the other end of the cable having means for effecting a connection with a safety harness, spring motor means carried by the base, positioned in the annular chamber in operative engagement with the internal gear for exerting a rotary force on the drum in a direction to wind the cable thereonto, said helical gear and pinion forming means for producing a force component in a direction to move the drum towards latching position when the cable is unwound therefrom, whereby when the cable is unwound at a fast rate the drum will be moved into latching position, and manually operable means for shifting the drum along its pivot and for returning the drum to unlatched position.

5. A device in accordance with claim 4 in which the base is provided with a permanent magnet that surrounds the drum pivot in position to attract the drum and hold it in latched position.

6. A device in accordance with claim 4 in which the drum has two grooves in its peripheral surface and in which the means for manually shifting the drum in the direction of its pivot comprises, a slide positioned adjacent the drum for movement parallel to the drum axis, a pin projecting from one side of the slide into one of said grooves, and means comprising a cam member operatively associated with the slide for shifting it in either direction to move the drum from either of its two positions to the other.

References Cited inthe le of this patent UNITED STATES PATENTS 962,099 Reinhart et al June 2l, 1910 1,369,197 Serrurier Feb. 22, 1921 2,403,653 Geohegan et al. July 9, 1946 2,434,119 Nordmark Ian. 6, 1948 2,480,335 Nordmark Aug. 30, 1949 2,656,127 Bunch Oct. 20, 1953 

